[fix] remove engine neeva from settings.yml

Engine is broken and can't by used any longer as a simple XPath engine.
@allendema tested a engines/neeva.py version using json from the dom, but
without luck: There was some kind of captcha for pagination.

[1] https://github.com/searxng/searxng/issues/2007#issuecomment-1426061698

Closes: https://github.com/searxng/searxng/issues/2007


Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>